Conventionally, an illuminating device that is capable of emitting area light is known; and is used as a backlight unit for shining light onto a liquid crystal display panel of a liquid crystal display device. As such illuminating devices for the liquid crystal display device, there are a direct type, side-light type and the like.
Here, in an illuminating device of the direct type, a light source is disposed right under a liquid crystal display panel. On the other hand, in an illuminating device of the side-light type, a light guide plate is disposed right under a liquid crystal display panel; and a light source is so disposed as to face a predetermined side end surface of the light guide plate (e.g., see a patent document 1). In the illuminating device of the side-light type, when light is emitted from the light source, the light is introduced into the light guide plate via the predetermined side end surface of the light guide plate. And, the light introduced into the light guide plate turns into area light to shine onto the liquid crystal display panel.
FIG. 7 is a simplified view of a conventional illuminating device of the side-light type. With reference to FIG. 7, in the conventional illuminating device of the side-light type, a plurality of light-emitting diodes (LED) 101 are used as a light source. The plurality of LEDs 101 as the light source are disposed on the same flexible printed wiring board (FPC) 102 to be a module.
Besides, a light guide plate 103 that converts the light from the LED 101 into area light is composed of a transparent plate member, and has: four side end surfaces; a front surface and a rear surface that are perpendicular to the four side end surfaces. A predetermined side end surface of the four side end surfaces of the light guide plate 103 is a surface which is disposed to face the LED 101 and functions as a light incident surface that introduces the light from the LED 101 into the light guide plate 103. Besides, the front surface of the light guide plate 103 is a surface that faces toward a liquid crystal display panel (not shown) and functions as a light output surface which outputs the light introduced into the light guide plate 103 as the area light to the liquid crystal display panel. And, the fixing of the LED 101 with respect to the light guide plate 103 is performed by adhering part of the FPC 102, on which the LED 101 is disposed, to the rear surface of the light guide plate 103.
In the above conventional structure, the LED 101, the light guide plate 103 and the like are used with housed in the inside of a case member (not shown) (e.g., see a patent document 2). The case member in which the LED 101, the light guide plate 103 and the like are housed has, for example: a bottom portion; and four side portions which are disposed upright on an outer circumferential portion of the bottom portion; and is formed into a box shape in such a way that a region enclosed by the four side portions on the bottom portion serves as a housing space. And, an opening side (opposite to the bottom portion side) of the case member is closed by a liquid crystal display panel (no shown) that is illuminated by the illuminating device.